Wear inhibitors for iron carbonyl



merciall'y. 1

Patented Mar. 27, 1951 V 2,546,421 WEAR INHIBITORS FOR IRON CARBONYL Earl Bartholomew, Birmingham, Mich., and Howard Clinton Cross, Columbus, Ohio, assignors, by direct and mesne assignments, to Ethyl Corporation, New York, N. Y., a corporation of Delaware No Dawns; Application August 5, 1949,

' Serial No. 108,852

- This invention relates to antiknock mixtures and-particularly to a mixture of iron carbonyl and an'inhibitor which reduces the engine wear caused by the use of the iron carbonyl.

Iron pentacarbonyl is a good antiknock agent and as such compares favorably with tetraethyllead. It has the economic advantage of being -cheap.'- However, when a fuel -c ontaining it is burned in internal combustion engines, it has the disadvantage of causing wear in engine parts,

particularly wearof the piston rings. The abrasive-prop'erties of iron carbonyl decomposition products have eifectively prevented its use com- It is, therefore, an object of this invention to provide a wear inhibitor which substantially re- 'duce's such engine wear. we have found that certain gasoline-soluble organic metallic compounds substantially reduce the' engine wear caused by the use of iron carbonyl. These com- 6 Claims. (c1i252-sss Our preferred inhibitors are gasoline soluble organic metallic compounds containing either sulphur or oxygen through which the metallic component is attached to the organic radical.

Among such inhibitors are the metal enolates includin acylacetonates, such as acetylacetonate pounds contain a metal characterized by its oxide having a scratch hardness of not more than 6, as determined byMohs scale of hardness test. Further, we-prefer that the molecular weight of the organic radical contained in these gasoline-soluble organic metallic compounds be between about '75 and 250;

Although it is to be understood that we are not bound by any theory, it is our belief that complex'compounds are formed between the decomposition products of iron carbonyl and our organic-metallic compounds. Such complex compounds are largely removed through the exhaust of the engine and there is a minimum of exposure to the vital'engine parts such as the piston rings. To the extent that these compounds are deposited in the engine, they are less abrasive than the iron oxide which would be formed in their absence: However, regardless'of any theory we have found that the organic me- "tallic compounds having the above properties decrease the engine wear obtained with iron carbonylalone. Furthermore, in addition to such properties, a good wear inhibitor should be stable in the presence'of water and insoluble therein, it should be stable to air at ordinary temperatures and it should have engine inductibility. The term engine inductibility refers to the ability of the inhibitor to be transported from the carburetor into the combustion chamber and depends simultaneously on several physical properties, namely state of aggregation, volatility, solubility and stability. The use of a small amount of an inert hydrocarbon carrier such as one-half to one per cent of saturated machine oil in the fuel enhances engine inductibility.

and propionylacetonates, alkylaminomethylene acetonates, such as m'ethylaminomethylene acetonates and ethylaminomethylene acetonates; the "metal-salts of carboxylic acidsdncluding naphthenates, alkylphthalates, such as butyl phthalateand 2-ethy1hexyl phthalate, and alkQI'IYIT'SUCClHlIilatES; andmetal salts of alkylcarbamic acids and their sulfur analogs, such as dibutylcarbamate, dibutyldithiocarbamate, diamyldithiocarbamate and di-(2-ethy1hexyl) -dithiocarbamate. However, organic derivatives of certain of the metalloids,such as triphenyl arsine and triphenyl antimonyalso substantially reduce the wear. Among the metals which can be used in derivatives of the above organic compounds are copper, barium, strontium, cobalt, calcium, zinc," antimony, silver, cerium, arsenic, indium, nickel, titanium, manganese, thorium, thallium, cadmium, tin, mercury, tellurium and sodium. Preferably the metal in our organic metallic Wear inhibitors is in the bivalent to tetravalent state.

Our invention can be further understood by referring to the following example:

' Alouantity of .fuel was prepared by blending in a'commercialmotor gasoline'a mixture of 0.312 'gram of copper as copper methylaminomethyleneacetonate, 3 cubic centimeters of iron I pentacarbonyl, and 21 cubic centimeters of a light' saturated machine. oil, all quantities of added materials based on .1 gallon of fuel. This fuel mixture was burned in a four-cycle single cylinder internal combustion engine for 150 hours. The internal diameter of the cylinder andthe weight of the piston rings of the engine were measured before and after this operation. The increase in diameter of the cylinder and the loss in weight of the piston rings are a measure of the wear obtained. In a similar operation keeping all quantities of materials used and engine conditions the same except that no wear inhibitor was used, the same'measurements for indicating wear were made. Comparing these two operations as to amount of wear obtained with and without an inhibitor and taking the wear resulting from the use of iron carbonyl alone as the operation using the copper inhibitor resulted in only 39% of the wear obtained for iron carbonyl alone. Thus the addition of a small quantity of the copper inhibitor to a fuel containing iron pentacarbonyl reduced the wear by 61% compared with that obtained with the same fuel without the inhibitor.

Using the same procedure and the same amount of metal in the form of the organic derivative, a number of operations on other organic metallic compounds were made. A summary of these results is given in the following table:

Per cent wgar s t h h d Name of inhibitor used with iron m i c pentacarbonyl 1n the fuel 58,5 g

alone Beryllium acetylacetonate 540 9. 0 Aluminum isopropoxide 336 9.0 Chromium acetylacetonate 130 3. 0 Zirconium naphthenate 121 7. 0 Uranium dibutyldithiocarbamate 129 6. 5 Triethylborate 125 7. 0

Iron carbonyl alone 100 1 6. 5

Titanium naphthenate 72 6.0 'Iriphcnyl arsine 70 3.0 Nickel dibutyldithiocarbamate 66 5. 5 Zinc naphthenate 63 4. 0 Triphenyl antimony 61 4. 0 Zinc dibutyldithiocarbamate 55 4. 0 Copper naphthenatd c 54 3. 5 Calcium naphthenate. 47 3. 5 Copper mcthylaminome neace tonate 39 3. 5 Copper ethylaminomethyleneacetonate 37 3. 5

1 Scratch hardness of iron oxide.

Further, a visual inspection of other engine parts such as journals, bearings and timing chains, in the above operations showed a simi- 'lar reduction in wear when one of our inhibitors was used with iron carbonyl.

The Mohs scratch hardness test, data from which are given in the above table for the metal oxide, is a standard one which can be made readily on the oxide of the metal desired for use. The hardness of the oxides varies between the limits of 0 to 10. This test is described in Danas Textbook of Mineralogy 4th edition, by W. E. Ford, 1932.

The above table shows the definite relationship existing between the amount of engine Wear and the scratch hardness of the oxide of the metal, which is by and large independent of the organic radical attached to the metal. Although the type of organic radical does have some effect on the engine wear, it is believed that it serves primarily as a means of getting the metal into solution in the gasoline, and transporting it into the combustion chamber of the engine. Therefore, our invention is not limited to the specific, organic radicals given herein. From the above table it is readily seen that if metals are used whose oxides have a scratch hardness above 6, the amount of wear is increased over iron carbonyl alone. On the other hand, by using metals the scratch hardness of the oxides of which is below 6, a substantial reduction in the engine wear caused by the iron carbonyl is obtained.

Generally, the amount of iron carbonyl to be used as an antiknock in fuels for engines is between about 1 and 3 cubic centimeters per galion of fuel. The amount of wear inhibitor used depends on the amount of iron carbonyl used and the inhibitor employed. In all cases the amount of inhibitor used is small and carries between approximately 0.05 to 0.25 gram of metal in the form of a metallic organic compound to one'cubic centimeter of iron carbonyl.

Our wear inhibitors can be used in mixtures containing iron carbonyl and other antiknock materials such as lead antiknock compounds. Also a mixture of iron carbonyl and one of our wear inhibitors can be used as an auxiliary antiknock fluid in an engine operating on a leaded gasoline. Such an auxiliary fluid is introduced into the engine only at the times needed to meet its antiknock requirements.

We claim:

1. An antiknock mixture consisting essentially of iron pentacarbonyl and a wear inhibitor in an amount sufficient to reduce wear in engine parts due to iron pentacarbonyl, said wear inhibitor consisting essentially of at least one gasoline soluble organic metallic compound having the formula RXM where R is an organic radical having a molecular weight between about and 250, :c is a numeral from 2 to 4 inclusive, and M is a metal whose oxide has a scratch hardness of not more than 6. 1

2. The mixture of claim 1 further defined in that the organic metallic compound is a metal enolate.

3. The mixture of claim. 1 further defined in that the organic metallic compound is a metal salt of a carboxylic acid.

4. The mixture of claim 1 further defined in that the organic metallic compound is a metal salt of a carbamic acid.

5. The mixture as defined by claim 1 in which the organic radical has a molecular weight of from about '75 to about 250, and the inhibiting ingredient and the iron pentacarbonyl are in such proportion that between about 0.05 and 0.25 gram of said metal is present for each cubic centimeter of iron pentacarbonyl.

6. The mixture as defined by claim 1 in which the inhibiting ingredient and the iron pentacarbonyl are in such proportion that between about 0.05 and 0.25 gram of said metal is present for each cubic centimeter of iron pentacarbo-nyl.

EARL BARTHOLOMEW. HOWARD CLINTON CROSS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 7 

1. AN ANTIKNOCK MIXTURE CONSISTING ESSENTIALLY OF IRON PENTACARBONYL AND A WEAR INHIBITOR IN AN AMOUNT SUFFICIENT TO REDUCE WEAR IN ENGINE PARTS DUE TO IRON PENTCARBONYL, SAID WEAR INHIBITOR CONSISTING ESSENTIALLY OF AT LEAST ONE GASOLINE SOLUBLE ORGANIC METALLIC COMPOUND HAVING THE FORMULA RXM WHERE R IS AN ORGANIC RADICAL HAVING A MOLECULAR WEIGHT BETWEEN ABOUT 75 AND 250, X IS A NUMERAL FROM 2 TO 4 INCLUSIVE, AND M IS A METAL WHOSE OXIDE HAS A SCRATCH HARDNESS OF NOT MORE THAN
 6. 